This invention relates to a safety guard for a heating apparatus. More specifically, it relates to a guard that covers both the emitter and dome lid, providing additional protection compared to guards that allow the dome lid or the top of the emitter to remain exposed.
High efficiency heating apparatuses are available for warming a preselected outdoor area. It has become fashionable to sit outdoors, on a patio, deck or other open space, using a patio heater to supply warmth when the evening becomes chilly. Generally the units comprise a propane tank, a standard that holds an emitter a sufficient distance from the ground, a burner to support the combustion or propane and a dome cover. The dome reflects much of the heat due to both convection and radiation downward toward the persons trying to keep warm. Details of preferred patio heaters are described in U.S. Pat. No. 6,102,031, U.S. Ser. No. 09/640,199, and U.S. Ser. No. 29/143,937 herein incorporated by reference.
Persons seated around a table, however, may not receive the full benefit of the heating apparatus because of their location. If the standard is tall enough to provide heat over the heads of standing persons, the heat may dissipate before it gets low enough to fully benefit those sitting down. Mini-heaters, that rest on a table top, have become popular for such situations. These smaller heaters use a shorter standard, keeping the warm air at a lower level.
One shortcoming of patio heaters is that the emitter and the dome become very hot due to contact with the hot gasses generated by combustion of the propane. Hot gasses from the emitter have a tendency to rise, and collect under the concave dome covers most commonly found on patio heaters. As the hot gasses are trapped by the dome and cannot rise to escape, heat transfers from the hot gasses to the dome. When there is no wind to carry the heat away, the dome can reach temperatures of several hundred degrees. If the hot surfaces are touched by accident or by curious children who are unaware of the danger, serious burns could result.
The prior art provides guards for an emitter of a portable heater. Design of emitter guards is specified in safety standards, such as Canadian Standards Association (xe2x80x9cCSAxe2x80x9d) Standard 5-90US for gas fired infrared patio heaters. With guards or other protective devices in place, any heater surface that is accessible by a conical probe 5xc2xd inches in length and up to 2xc2xe inches in diameter shall not exceed 180xc2x0 F. above ambient temperature. Surfaces are also required to be cool enough that clothing does not ignite when brought in contact with the heater. The standard currently excludes any surface that is located more than 6.5 feet above the ground, which excludes the dome of most full size heaters. Conventional patio heaters with high standards are tall enough to provide some protection from touching of the dome under normal circumstances. Both the dome and the emitter are out of the reach of children, and are generally over the head of most standing adults.
There are times, however, when it is possible to touch the dome of an outdoor heater. After use, for example, two users may tip the unit, with one of them grabbing the dome to move it to a different location. The dome of a mini-heater may be within the reach of a curious child climbing on a picnic table. When located on a table top, the dome of a mini-heater is at a height of approximately six feet, within the reach of most adults, and within the range of surfaces tested according to the CSA standard 5-90US.
These, as well as a number of other examples, demonstrate the need to protect consumers from touching the dome of a portable heater. There is currently no standard providing a guard for the dome of a patio heater, and none are known in the prior art.
It is therefore an object of this invention to provide an improved guard for a portable heater that limits access to the surface of the dome cover.
It is another object of this invention to provide an improved guard for a table top gas fired patio heater that meets the requirements of CSA standard 5-90US.
It is still another object of this invention to provide an improved guard for a portable heater that limits access to the surface of the entire emitter and dome cover.
It is yet another object of this invention to provide an improved guard for a portable heater that is economical to make and to ship so as to minimize the cost of the safety guard.
These and other objects are met or exceeded by the present invention which features a dome guard for a dome cover of a heating apparatus. Use of the dome guard, either alone, or together with an emitter guard, reduces the chance of bums resulting from contact of a user""s skin with the hot dome cover.
More specifically, the present invention provides a dome guard for a dome cover having an inside surface, an outside surface and a rim. The dome guard includes a heat resistant grid, at least one standoff for holding the dome guard a first predetermined distance from the dome cover, and a clip for engaging the rim of the dome cover. Contact of human skin with the rim of the dome is limited by the clip, which holds the dome guard a second predetermined distance from the rim of the dome.
By enclosing the dome in a wire grid that is maintained a predetermined distance away from the dome surface, access to the surface of the dome is limited and heat has a chance to dissipate in the intervening space. Contact of the hot surfaces, either by a child or by accident, is minimized. Although the dome guard is likely to itself become very warm, the severity of any bums that might result will be greatly reduced compared to touching of the hot surface itself. Further, the temperature of the dome guard would be insufficient to cause clothing to ignite if the clothing came in contact with the dome guard surface. Table top heaters are likely to have the dome surface within the 6xc2xd foot height restriction, below which all of the surfaces must comply with the limitations of the standard. Thus it is important that the design of the dome guard meet requirements of CSA standard 5-90US.
Installation of the dome guard on the dome is also easy using the present invention. When it is desirable to install the dome guard, the dome is removed from the heating apparatus. The dome guard is then oriented with the standoffs against the top outside surface of the dome. The dome guard is then flexed, pushing the rim of the dome guard downward until the clips engage with the rim of the dome, holding the guard in place.